Conductive compositions (conductive pastes) containing a conductive metal powder (conductive filler) such as a silver paste have been used for forming electrodes or circuits of electronic components. Of these, in the conductive paste containing a thermoplastic or thermosetting resin, usually, conductivity is realized by the contact of conductive fillers one another resulting from the shrinkage of the used resin, and also close contact or adhesiveness to a base material is secured by the presence of the resin. Therefore, in the conductive paste containing such a binder, in order to obtain sufficient conductivity, it is important to increase the contact area between the conductive metal powders. From this point of view, as the conductive metal powder, an attempt of using a metal flake (a flaky metal powder) has been made.
For example, Patent Document 1 discloses a conductive paste containing a flaky silver powder and an organic resin. The document exemplifies, as the organic resin, a wide range of organic resins such as polyester resins, modified polyester resins (urethane-modified polyester resins etc.), polyether-urethane resins, polycarbonate-urethane resins, vinyl chloride-vinyl acetate copolymers, epoxy resins, phenolic resins, acrylic resins, polyamideimides, nitrocellulose, cellulose acetate butyrate, and cellulose acetate propionate. In particular, polyester resins and urethane-modified polyester resins are used in Examples from the viewpoints of bending resistance and the like.
Moreover, Patent Document 2 discloses a flaky silver powder in which the average particle diameter and the BET specific surface area have a specific relationship. In this document, as the resin used in the conductive paste, there are exemplified epoxy resins, acrylic resins, polyester resins, polyimide resins, polyurethane resins, phenoxy resins, silicone resins, and the like and polyester resins are used in Examples.
In such a situation, a further improvement in conductivity and adhesiveness has been desired.